/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.plan.planner.plan.node.metedata.write;

import org.apache.iotdb.common.rpc.thrift.TRegionReplicaSet;
import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.commons.path.PathDeserializeUtil;
import org.apache.iotdb.db.conf.IoTDBDescriptor;
import org.apache.iotdb.db.mpp.plan.analyze.Analysis;
import org.apache.iotdb.db.mpp.plan.planner.plan.node.*;
import org.apache.iotdb.tsfile.exception.NotImplementedException;
import org.apache.iotdb.tsfile.file.metadata.enums.CompressionType;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.file.metadata.enums.TSEncoding;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;

import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;

public class CreateMultiTimeSeriesNode extends WritePlanNode {

    private static final int SPLIT_SIZE =
            IoTDBDescriptor.getInstance().getConfig().getMaxMeasurementNumOfInternalRequest();

    private final Map<PartialPath, MeasurementGroup> measurementGroupMap;

    private TRegionReplicaSet regionReplicaSet;

    public CreateMultiTimeSeriesNode(PlanNodeId id) {
        super(id);
        measurementGroupMap = new HashMap<>();
    }

    public CreateMultiTimeSeriesNode(
            PlanNodeId id,
            List<PartialPath> paths,
            List<TSDataType> dataTypes,
            List<TSEncoding> encodings,
            List<CompressionType> compressors,
            List<Map<String, String>> propsList,
            List<String> aliasList,
            List<Map<String, String>> tagsList,
            List<Map<String, String>> attributesList) {
        super(id);
        measurementGroupMap = new HashMap<>();

        // gather measurements of same device
        int size = paths.size();
        PartialPath devicePath;
        MeasurementGroup measurementGroup;
        for (int i = 0; i < size; i++) {
            devicePath = paths.get(i).getDevicePath();
            measurementGroup = measurementGroupMap.get(devicePath);
            if (measurementGroup == null) {
                measurementGroup = new MeasurementGroup();
                measurementGroupMap.put(devicePath, measurementGroup);
            }

            measurementGroup.addMeasurement(
                    paths.get(i).getMeasurement(), dataTypes.get(i), encodings.get(i), compressors.get(i));

            if (propsList != null) {
                measurementGroup.addProps(propsList.get(i));
            }

            if (aliasList != null) {
                measurementGroup.addAlias(aliasList.get(i));
            }

            if (tagsList != null) {
                measurementGroup.addTags(tagsList.get(i));
            }

            if (attributesList != null) {
                measurementGroup.addAttributes(attributesList.get(i));
            }
        }
    }

    public CreateMultiTimeSeriesNode(
            PlanNodeId planNodeId, Map<PartialPath, MeasurementGroup> measurementGroupMap) {
        super(planNodeId);
        this.measurementGroupMap = measurementGroupMap;
    }

    private CreateMultiTimeSeriesNode(
            PlanNodeId planNodeId,
            Map<PartialPath, MeasurementGroup> measurementGroupMap,
            TRegionReplicaSet regionReplicaSet) {
        super(planNodeId);
        this.measurementGroupMap = measurementGroupMap;
        this.regionReplicaSet = regionReplicaSet;
    }

    private void addMeasurementGroup(PartialPath devicePath, MeasurementGroup measurementGroup) {
        measurementGroupMap.put(devicePath, measurementGroup);
    }

    public Map<PartialPath, MeasurementGroup> getMeasurementGroupMap() {
        return measurementGroupMap;
    }

    @Override
    public List<PlanNode> getChildren() {
        return new ArrayList<>();
    }

    @Override
    public void addChild(PlanNode child) {
    }

    @Override
    public PlanNode clone() {
        throw new NotImplementedException("Clone of CreateMultiTimeSeriesNode is not implemented");
    }

    @Override
    public int allowedChildCount() {
        return NO_CHILD_ALLOWED;
    }

    @Override
    public List<String> getOutputColumnNames() {
        return null;
    }

    @Override
    public <R, C> R accept(PlanVisitor<R, C> visitor, C schemaRegion) {
        return visitor.visitCreateMultiTimeSeries(this, schemaRegion);
    }

    public static CreateMultiTimeSeriesNode deserialize(ByteBuffer byteBuffer) {
        Map<PartialPath, MeasurementGroup> measurementGroupMap = new HashMap<>();
        int size = byteBuffer.getInt();
        PartialPath devicePath;
        MeasurementGroup measurementGroup;
        for (int i = 0; i < size; i++) {
            devicePath = (PartialPath) PathDeserializeUtil.deserialize(byteBuffer);
            measurementGroup = new MeasurementGroup();
            measurementGroup.deserialize(byteBuffer);
            measurementGroupMap.put(devicePath, measurementGroup);
        }

        PlanNodeId planNodeId = PlanNodeId.deserialize(byteBuffer);
        return new CreateMultiTimeSeriesNode(planNodeId, measurementGroupMap);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        CreateMultiTimeSeriesNode that = (CreateMultiTimeSeriesNode) o;
        return this.getPlanNodeId().equals(that.getPlanNodeId())
                && Objects.equals(measurementGroupMap, that.measurementGroupMap);
    }

    @Override
    protected void serializeAttributes(ByteBuffer byteBuffer) {
        PlanNodeType.CREATE_MULTI_TIME_SERIES.serialize(byteBuffer);

        ReadWriteIOUtils.write(measurementGroupMap.size(), byteBuffer);
        for (Map.Entry<PartialPath, MeasurementGroup> entry : measurementGroupMap.entrySet()) {
            entry.getKey().serialize(byteBuffer);
            entry.getValue().serialize(byteBuffer);
        }
    }

    @Override
    protected void serializeAttributes(DataOutputStream stream) throws IOException {
        PlanNodeType.CREATE_MULTI_TIME_SERIES.serialize(stream);

        ReadWriteIOUtils.write(measurementGroupMap.size(), stream);
        for (Map.Entry<PartialPath, MeasurementGroup> entry : measurementGroupMap.entrySet()) {
            entry.getKey().serialize(stream);
            entry.getValue().serialize(stream);
        }
    }

    public int hashCode() {
        return Objects.hash(this.getPlanNodeId(), measurementGroupMap);
    }

    @Override
    public TRegionReplicaSet getRegionReplicaSet() {
        return regionReplicaSet;
    }

    public void setRegionReplicaSet(TRegionReplicaSet regionReplicaSet) {
        this.regionReplicaSet = regionReplicaSet;
    }

    @Override
    public List<WritePlanNode> splitByPartition(Analysis analysis) {
        // gather devices to same target region
        Map<TRegionReplicaSet, Map<PartialPath, MeasurementGroup>> splitMap = new HashMap<>();
        for (Map.Entry<PartialPath, MeasurementGroup> entry : measurementGroupMap.entrySet()) {
            TRegionReplicaSet regionReplicaSet =
                    analysis.getSchemaPartitionInfo().getSchemaRegionReplicaSet(entry.getKey().getFullPath());
            splitMap
                    .computeIfAbsent(regionReplicaSet, k -> new HashMap<>())
                    .put(entry.getKey(), entry.getValue());
        }

        // split each region's requests to ensure each request is not that huge, which makes the system
        // more stable and may enhance the concurrency
        List<WritePlanNode> result = new ArrayList<>();
        for (Map.Entry<TRegionReplicaSet, Map<PartialPath, MeasurementGroup>> entry :
                splitMap.entrySet()) {
            for (Map<PartialPath, MeasurementGroup> measurementGroupMap :
                    splitAndRegroupMeasurements(entry.getValue())) {
                result.add(
                        new CreateMultiTimeSeriesNode(getPlanNodeId(), measurementGroupMap, entry.getKey()));
            }
        }

        return result;
    }

    private static List<Map<PartialPath, MeasurementGroup>> splitAndRegroupMeasurements(
            Map<PartialPath, MeasurementGroup> measurementGroupMap) {
        List<Map<PartialPath, MeasurementGroup>> result = new ArrayList<>();
        // keep measurements of same device as much as possible
        int tmpSum = 0;
        Map<PartialPath, MeasurementGroup> tmpMap = new HashMap<>();
        for (Map.Entry<PartialPath, MeasurementGroup> entry : measurementGroupMap.entrySet()) {
            if (entry.getValue().size() > SPLIT_SIZE) {
                for (MeasurementGroup splitMeasurementGroup : entry.getValue().split(SPLIT_SIZE)) {
                    if (splitMeasurementGroup.size() == SPLIT_SIZE) {
                        Map<PartialPath, MeasurementGroup> singletonMap = new HashMap<>();
                        singletonMap.put(entry.getKey(), splitMeasurementGroup);
                        result.add(singletonMap);
                    } else {
                        // each device has at most one splitMeasurementGroup with size < splitSize
                        if (tmpSum + splitMeasurementGroup.size() > SPLIT_SIZE) {
                            result.add(tmpMap);
                            tmpMap = new HashMap<>();
                            tmpSum = 0;
                        }
                        tmpSum += splitMeasurementGroup.size();
                        tmpMap.put(entry.getKey(), splitMeasurementGroup);
                    }
                }
            } else {
                if (tmpSum + entry.getValue().size() > SPLIT_SIZE) {
                    result.add(tmpMap);
                    tmpMap = new HashMap<>();
                    tmpSum = 0;
                }
                tmpSum += entry.getValue().size();
                tmpMap.put(entry.getKey(), entry.getValue());
            }
        }

        if (!tmpMap.isEmpty()) {
            result.add(tmpMap);
        }

        return result;
    }
}
